Derivatives of 2-(1-benzyl-1h-pyrazolo(3,4-b)pyridine-3-yl)- 5(-4-pyridiny)l-4- pyrimidinamines and the use thereof as quanylate cyclase stimulators

ABSTRACT

The invention relates to novel chemical compounds of formula (I), which stimulate soluble guanylate cyclase, to the production and use thereof as medicament, particularly in the treatment of cardiovascular diseases and/or sexual dysfunction (I), wherein R 1 ″ represents chlorine, cyano, trifluoromethyl or methoxy and R 2  represents hydrogen or fluorine or R 1  represents fluorine and R 2  represents fluorine. The invention also relates to the salts, isomers and hydrates of said compounds.

Derivatives of2-(1-benzyl-1H-pyrazolo(3,4-B)pyridine-3-yl)-5-(4-pyridinyl)-4-pyrimidinaminesand the use thereof as guanylate cyclase stimulators

The present invention relates to chemical compounds which stimulatesoluble guanylate cyclase, to the preparation thereof and to the usethereof as medicaments, in particular as medicaments for the treatmentof cardiovascular disorders and/or sexual dysfunction.

One of the most important cellular transmission systems in mammaliancells is cyclic guanosine monophosphate (cGMP). Together with nitricoxide (NO), which is released from the endothelium and transmitshormonal and mechanical signals, it forms the NO/cGMP system. Guanylatecyclases catalyse the biosynthesis of cGMP from guanosine triposphate(GTP). The representatives of this family disclosed to date can bedivided both according to structural features and according to the typeof ligands into two groups: the particulate guanylate cyclases which canbe stimulated by natriuretic peptides, and the soluble guanylatecyclases which can be stimulated by NO. The soluble guanylate cyclasesconsist of two subunits and very probably contain one heme perheterodimer, which is part of the regulatory site. The latter is ofcentral importance for the mechanism of activation. NO is able to bindto the iron atom of heme and thus markedly increase the activity of theenzyme. Heme-free preparations cannot, by contrast, be stimulated by NO.CO is also able to attach to the central iron atom of heme, but thestimulation by CO is distinctly less than that by NO.

Through the production of cGMP and the regulation, resulting therefrom,of phosphodiesterases, ion channels and protein kinases, guanylatecyclase plays a crucial part in various physiological process, inparticular in the relaxation and proliferation of smooth muscle cells,in platelet aggregation and adhesion and in neuronal signaltransmission, and in disorders caused by an impairment of theaforementioned processes. Under pathophysiological conditions, theNO/cGMP system may be suppressed, which may lead for example to highblood pressure, platelet activation, increased cellular proliferation,endothelial dysfunction, atherosclerosis, angina pectoris, heartfailure, thromboses, stroke, sexual dysfunction and myocardialinfarction.

A possible way of treating such disorders which is independent of NO andaims at influencing the cGMP signal pathway in organisms is a promisingapproach because of the high efficiency and few side effects which areto be expected.

Compounds, such as organic nitrates, whose effect is based on NO have todate been exclusively used for the therapeutic stimulation of solubleguanylate cyclase. NO is produced by bioconversion and activates solubleguanylate cyclase by attaching to the central iron atom of haem. Besidesthe side effects, the development of tolerance is one of the crucialdisadvantages of this mode of treatment.

Some substances which directly stimulate soluble guanylate cyclase, i.e.without previous release of NO, have been described in recent years,such as, for example, 3-(5′-hydroxymethyl-2′-furyl)-1-benzylindazole(YC-1, Wu et al., Blood 84 (1994), 4226; Mülsch et al., Brit. J.Pharmacol. 120 (1997), 681), fatty acids (Goldberg et al, J. Biol. Chem.252 (1977), 1279), diphenyliodonium hexafluorophosphate (Pettibone etal., Eur. J. Pharmacol. 116 (1985), 307), isoliquiritigenin (Yu et al.,Brit. J. Pharmacol. 114 (1995), 1587) and various substituted pyrazolederivatives (WO 98/16223).

In addition, WO 98/16507, WO 98/23619, WO 00/06567, WO 00/06568, WO00/06569, WO 00/21954 WO 02/42299, WO 02/42300, WO 02/42301, WO02/42302, WO 02/092596 and WO 03/004503 describe pyrazolopyridinederivatives as stimulators of soluble guanylate cyclase. Also describedinter alia therein are pyrazolopyridines having a pyrimidine residue inposition 3. Compounds of this type have very high in vitro activity inrelation to stimulating soluble guanylate cyclase. However, it hasemerged that these compounds have disadvantages in respect of their invivo properties such as, for example, their behavior in the liver, theirpharmacokinetic behavior, their dose-response relation or theirmetabolic pathway.

It was therefore the object of the present invention to provide furtherpyrazolopyridine derivatives which act as stimulators of solubleguanylate cyclase but do not have the disadvantages, detailed above, ofthe compounds from the prior art.

This object is achieved by the present invention through the compoundsas claimed in claim 1. These novel pyrazolopyridine derivatives aredistinguished by a 4-amino-5-(pyridin-4-yl)pyrimidine residue inposition 3 and a substituted benzyl radical in position 1.

Specifically, the present invention relates to compounds of the formula(I)

in which

R¹ is chlorine, cyano, trifluoromethyl or methoxy,

and

R² is hydrogen or fluorine,

or

R¹ is fluorine, and

R² is fluorine,

and salts, isomers and hydrates thereof.

The compounds according to the invention of the formula (I) may also bein the form of their salts. Mention may generally be made here of saltswith organic or inorganic bases or acids.

Physiologically acceptable salts are preferred for the purposes of thepresent invention. Physiologically acceptable salts of the compoundaccording to the invention may be salts of the substances according tothe invention with mineral acids, carboxylic acids or sulfonic acids.Particularly preferred examples are salts with hydrochloric acid,hydrobromic acid, sulfuric acid, phosphoric acid, methanesulfonic acid,ethanesulfonic acid, p-toluenesulfonic acid, benzenesulfonic acid,naphthalenedisulfonic acid, acetic acid, propionic acid, lactic acid,tartaric acid, citric acid, fumaric acid, maleic acid or benzoic acid.

Physiologically acceptable salts may likewise be metal or ammonium saltsof the compound according to the invention having a free carboxyl group.Particularly preferred examples are sodium, potassium, magnesium orcalcium salts, and ammonium salts derived from ammonia or organic aminessuch as, for example, ethylamine, di- or triethylamine, di- ortriethanolamine, dicyclohexylamine, dimethylaminoethanol, arginine,lysine or ethylenediamine.

The compounds according to the invention may exist in tautomeric forms.This is known to the skilled person, and the invention likewiseencompasses such forms.

The compounds according to the invention may furthermore be in the formof their possible hydrates.

A symbol * on a bond denotes the product of linkage in the molecule.

Preference is given to compounds of the formula (Ia)

in which

R^(1a) is selected from the group of

and salts, isomers and hydrates thereof.

Preference is given to the compound of the formula (Ia) in which

R^(1a) is

and salts, isomers and hydrates thereof.

The compounds according to the invention of the formula (I) can beprepared by customary reaction steps familiar to the skilled person, forexample in analogy to the processes described for the synthesis of theexemplary embodiments.

The compounds according to the invention of the formula (I) show avaluable range of pharmacological effects which could not have beenpredicted.

The compounds according to the invention of the formula (I) bring aboutvasorelaxation and an inhibition of platelet aggregation and lead to areduction in blood pressure and an increase in coronary blood flow.These effects are mediated by direct stimulation of soluble guanylatecyclase and an intracellular increase in cGMP. In addition, thecompounds according to the invention of the formula (I) enhance theeffect of substances which increase the cGMP level, such as, forexample, EDRF (endothelium derived relaxing factor), NO donors,protoporphyrin IX, arachidonic acid or phenylhydrazine derivatives.

They can therefore be employed in medicaments for the treatment ofcardiovascular disorders such as, for example, for the treatment of highblood pressure and heart failure, stable and unstable angina pectoris,peripheral and cardiac vascular disorders, of arrhythmias, for thetreatment of thromboembolic disorders and ischemias such as myocardialinfarction, stroke, transitory and ischemic attacks, disturbances ofperipheral blood flow, prevention of restenoses as after thrombolysistherapies, percutaneous transluminal angioplasties (PTAs), percutaneoustransluminal coronary angioplasties (PTCAs), bypass and for thetreatment of arteriosclerosis, asthmatic disorders and diseases of theurogenital system such as, for example, prostate hypertrophy, erectiledysfunction, female sexual dysfunction, osteoporosis, glaucoma,pulmonary hypertension, gastroparesis and incontinence.

The compounds according to the invention of the formula (I) are alsosuitable for controlling central nervous system diseases characterizedby disturbances of the NO/cGMP system. They are suitable in particularfor improving perception, concentration, learning or memory aftercognitive impairments like those occurring in particular in associationwith situations/diseases/syndromes such as mild cognitive impairment,age-associated learning and memory impairments, age-associated memoryloss, vascular dementia, craniocerebral trauma, stroke, dementiaoccuring after strokes (post stroke dementia), post-traumaticcraniocerebral trauma, general concentration impairments, concentrationimpairments in children with learning and memory problems, Alzheimer'sdisease, Lewy body dementia, dementia with degeneration of the frontallobes including Pick's syndrome, Parkinson's disease, progressivenuclear palsy, dementia with corticobasal degeneration, amyolateralsclerosis (ALS), Huntington's disease, multiple sclerosis, thalamicdegeneration, Creutzfeld-Jacob dementia, HIV dementia, schizophreniawith dementia or Korsakoff's psychosis. They are also suitable for thetreatment of central nervous system disorders such as states of anxiety,tension and depression, CNS-related sexual dysfunctions and sleepdisturbances, and for controlling pathological disturbances of theintake of food, stimulants and addictive substances.

The compounds according to the invention of the formula (I) arefurthermore also suitable for controlling cerebral blood flow and thusrepresent effective agents for controlling migraine.

The compounds according to the invention of the formula (I) are alsosuitable for the prophylaxis and control of the sequelae of cerebralinfarctions such as stroke, cerebral ischemias and craniocerebraltrauma. They can likewise be employed for controlling states of pain.

In addition, the compounds according to the invention of the formula (I)have an anti-inflammatory effect and can therefore be employed asanti-inflammatory agents.

Furthermore the present invention also encompasses the combination of atleast one compound according to the invention of the formula (I) withone or more organic nitrates or NO donors.

Organic nitrates and NO donors for the purposes of the invention aregenerally substances which display their therapeutic effect via releaseof NO or NO species. Mention may be made by way of example andpreferably of: sodium nitroprusside, nitroglycerine, isosorbidedinitrate, isosorbide mononitrate, molsidomine and SIN-1.

In addition, the present invention also encompasses the combination withone or more compounds which inhibit breakdown of cyclic guanosinemonophosphate (cGMP). These are preferably inhibitors ofphosphodiesterases 1, 2 and 5; nomenclature of Beavo and Reifsnyder(1990), TiPS 11 pp. 150 to 155. Particularly preferred in thisconnection are inhibitors of phosphodiesterase 5 (PDE V inhibitors),especially one of the compounds sildenafil (Viagra™, EP-A 0 463 756, WO94/28902), vardenafil (WO 99/24433) or tadalafil (WO 95/19978). Theseinhibitors potentiate the effect of the compounds according to theinvention, and the desired pharmacological effect is increased.

The present invention further relates to medicaments which comprise atleast one compound according to the invention, preferably together withone or more pharmacologically acceptable excipients or carriers, and tothe use thereof for the aforementioned purposes.

The active ingredient may have systemic and/or local effects. For thispurpose, it can be administered in a suitable way such as, for example,oral, parenteral, pulmonary, nasal, sublingual, lingual, buccal, rectal,transdermal, conjunctival, topical or as implant.

The active ingredient can be administered in administration formssuitable for these administration routes.

Suitable for oral administration are known administration forms whichdeliver the active ingredient rapidly and/or in a modified manner, suchas, for example, tablets (uncoated and coated tablets, e.g. tabletsprovided with enteric coatings or film-coated tablets), capsules,sugar-coated tablets, granules, pellets, powders, emulsions,suspensions, solutions and aerosols.

Parenteral administration can take place with avoidance of an absorptionstep (intravenous, intraarterial, intracardiac, intraspinal orintralumbar) or with inclusion of an absorption (intramuscular,subcutaneous, intracutaneous, percutaneous, or intraperitoneal).Administration forms suitable for parenteral administration are, interalia, preparations for injection and infusion in the form of solutions,suspensions, emulsions, lyophilizates and sterile powders.

Suitable for the other routes of administration are, for example,pharmaceutical forms for inhalation (inter alia powder inhalers,nebulizers), nasal drops/solutions, sprays; tablets or capsules forlingual, sublingual or buccal administration, suppositories,preparations for the ears and eyes, vaginal capsules, aqueoussuspensions (lotions, shaking mixtures), lipophilic suspensions,ointments, creams, milk, pastes, dusting powders or implants, such as,for example, stents.

The active ingredients can be converted in a manner known per se intothe stated administration forms. This takes place with use of inertnon-toxic, pharmaceutically suitable excipients. These include, interalia, carriers (for example microcrystalline cellulose), solvents (forexample liquid polyethylene glycols), emulsifiers (for example sodiumdodecyl sulfate), dispersants (for example polyvinylpyrrolidone),synthetic and natural biopolymers (for example albumin), stabilizers(for example antioxidants such as ascorbic acid), colourings (forexample inorganic pigments such as iron oxides) or masking flavoursand/or odours. The active ingredient can, where appropriate, be presentalso in microencapsulated form in one or more of the carriers indicatedabove.

The therapeutically effective compound of the formula (I) should bepresent in the pharmaceutical preparations detailed above in aconcentration of about 0.1 to 99.5, preferably of about 0.5 to 95, % byweight of the complete mixture.

The pharmaceutical preparations detailed above may, apart from thecompound according to the invention of the formula (I) also containother active pharmaceutical ingredients.

It has generally proved to be advantageous both in human and inveterinary medicine to administer the active ingredient according to theinvention in total amounts of about 0.001 to about 50, preferably 0.001to 10, mg/kg of body weight every 24 hours, where appropriate in theform of a plurality of single doses, to achieve the desired results. Asingle dose contains the active ingredient according to the inventionpreferably in amounts of about 0.001 to about 30, in particular 0.001 to3, mg/kg of body weight.

The present invention is explained in more detail below by means ofnon-restrictive preferred examples. Unless indicated elsewhere, allquantitative data relate to percentages by weight. Solvent ratios,dilution ratios and concentration data for liquid/liquid solutionsrelate in each case to volume.

Biological Investigations

Vasorelaxant Effect In Vitro

Rabbits are stunned by a blow to the back of the neck and areexsanguinated. The aorta is removed, freed of adherent tissue anddivided into rings 1.5 mm wide, which are put singly under tension in 5ml organ baths containing carbogen-gassed Krebs-Henseleit solution at37° C. with the following composition (mM): NaCl: 119; KCl: 4.8; CaCl₂×2H₂O; MgSO₄×7 H₂O: 1.4; KH₂PO₄: 1.2; NaHCO₃: 25; glucose: 10. The forceof contraction is detected with Statham UC2 cells, amplified anddigitized via A/D converters (DAS-1802 HC, Keithley Instruments Munich)and recorded in parallel on chart recorders. A contraction is generatedby adding phenylephrine to the bath cumulatively in increasingconcentration. After several control cycles, the substance to beinvestigated is investigated in each further run in increasing dosage ineach case, and the height of the contraction is compared with the heightof the contraction reached in the last preceding run. The concentrationnecessary to reduce the height of the control value by 50% (IC₅₀) iscalculated from this. The standard application volume is 5 μl, and theDMSO content in the bath solution corresponds to 0.1%.

Rabbit Model

Adult male chinchilla rabbits weighing 3-5 kg are adapted to being keptsingly for several days after delivery. They have free access to waterand can take feed for two hours a day. The animals are kept in a10/14-hour day/night rhythm (light on from 8.00 h), and the roomtemperature is 22-24° C.

Three to six animals are used in each treatment group and are weighedimmediately before the start of the test. For the i.v. administration,the substances are dissolved in Transcutol (GATTEFOSSE GmbH) and dilutedin the ratio 3/7 with a 20% strength Cremophor solution (Cremophor(BASF), water). A volume of 0.5 ml/kg is injected into the ear vein.Water-soluble substances are injected in 0.9% sodium chloride solution.

For oral administration, the test substances are dissolved in a6:10:9.69 glycerol:water:polyethylene glycol mixture and administered bygavage in a volume of 1 ml/kg.

Under resting conditions, the rabbit penis is invisible in the pubicregion and is completely covered by the penis skin. The erection isassessed by measuring the length of the protruding penis with a slidecalliper. The measurement is carried out 5, 10, 15, 30, 45, 60 and 120minutes after administration of the substance and, after oraladministration, additionally after 3, 4, 5 and 6 hours. The animals arefor this purpose removed from the cage each time, held firmly by theneck fur and the rear paws, turned on their backs and measured.Corresponding solvent controls are carried out. (Compare reference: E.Bischoff, K. Schneider, Int. J. of Impotence Res. 2001, 13, 230-235; E.Bischoff, U. Niewoehner, H. Haning, M. Es Sayed, T. Schenke, K. H.Schlemmer, The Journal of Urology, 2001, 165, 1316-1318; E. Bischoff,Int. J. Impotence Res. 2001, 13, 146-148).

Determination of Pharmacokinetic Parameters after Intravenous and OralAdministration

The substance to be investigated is administered intravenously assolution to animals (e.g. mice, rats, dogs), and oral administrationtakes place as solution or suspension by gavage. After administration ofthe substance, blood is taken from the animals at fixed times and isheparinized, and then plasma is obtained therefrom by centrifugation.The substance is quantified analytically in the plasma by LC/MS/MS. Theplasma concentration/time courses found in this way are used tocalculate the pharmacokinetic parameters by means of a validatedpharmacokinetic computer program.

Inhibition of Cytochrome P450 Enzymes

The potential for inhibition of P-450 isoenzymes which are important formetabolism is investigated automatically in a 96-well format. Twodifferent assays are used for this.

In the assay based on the formation of fluorescent metabolites,recombinant enzymes (e.g. CYP1A2, 2C8, 2C9, 2C19, 2D6 or 3A4) and ingeneral substrates containing fluorescein or coumarin partial structuresare employed. In each case one substrate concentration and 8concentrations of the potential inhibitor are used. After incubationwith the particular recombinant CYP enzyme, a fluorescence reader isused to measure the extent of fluorescent metabolites compared with thecontrol (without inhibitor), and an IC₅₀ is calculated [Anal. Biochem.248, 188 (1997)].

In the 2nd assay, human liver microsomes are used as enzyme source, andthe CYP isoform-selective substrates used are phenacetin (CYP1A2),diclofenac (CYP2C9), dextromethorphan (CYP2D6) and midazolam (CYP3A4).The formation of the particular metabolite is measured using LC-MS/MS.Assuming that inhibition is competitive, K_(i) values are calculatedfrom the reduction in metabolite formation compared with the control (1substrate and 3 inhibitor concentrations).

Induction of Cytochrome P450 Enzymes in Human Liver Cell Cultures

To investigate the potential for side effects of the substancesaccording to the invention in relation to induction of cytochrome P450enzymes, primary human hepatocytes are cultured with a cell density of2.5×10⁵ cells between two layers of collagen in 24-well microtiterplates at 37° C. with 5% CO₂ for 8 days. The cell culture medium ischanged each day.

After 48 hours in culture, the hepatocytes are treated with differentconcentrations of the test substances, comparing with the inducersrifampicin (RIF; 50 μM), omeprazole (OME; 100 μM) and phenobarbital (PB;2 mM), in duplicate determination for 5 days. The final concentrationsof the test substances are 0.01-10 μg/ml.

The inductive effect of the test substances on the cytochrome (CYP) P450enzymes 1A2, 2B6, 2C19 and 3A4 is determined by adding the substrates7-ethoxyresorufin (CYP1A2), [¹⁴C]-S-mephenytoin (CYP2B6 and 2C19) and[¹⁴C]-testosterone (CYP3A4) to the cell cultures on day 8. The inductivepotential of the test substances is found from the activities, measuredin this way, of CYP1A2, 2B6, 2C19 and 3A4 enzymes of treated cellscompared with untreated cells.

Synthesis of Starting Compounds and Exemplary Embodiments

Abbreviations:

-   ACN acetonitrile-   conc. concentrated-   DCI direct chemical ionization (in MS)-   DCM dichloromethane-   DIEA N,N-diisopropylethylamine-   DMAP dimethylaminopyridine-   DMSO dimethyl sulfoxide-   DMF N,N-dimethylformamide-   EA ethyl acetate-   EI electron impact ionization (in MS)-   eq. equivalent-   equiv. equivalent-   ESI electrospray ionization (in MS)-   H hour-   HPLC high pressure, high performance liquid chromatography-   LC-MS coupled liquid chromatography/mass spectroscopy-   LDA lithium diisopropylamide-   m.p. melting point-   MS mass spectroscopy-   NMR nuclear magnetic resonance spectroscopy-   RP-HPLC reverse phase HPLC-   RT room temperature-   R_(t) retention time (in HPLC)-   sat. saturated-   THF tetrahydrofuran-   TLC thin layer chromatography    LC/MS and HPLC Methods    Method 1 (LCMS)

Instrument: Micromass Platform LCZ, HP1100; column: Symmetry C18, 50mm×2.1 mm, 3.5 μm; Eluent A: water+0.05% formic acid, Eluent B:acetonitrile+0.05% formic acid; Gradient: 0.0 min 90% A→4.0 min 10%A→6.0 min 10% A; oven: 40° C.; flow rate: 0.5 ml/min; UV detection:208-400 nm.

Method 2 (LCMS)

Instrument: Waters Alliance 2790 LC; column: Symmetry C18, 50 mm×2.1,3.5 μm; Eluent A: water+0.1% formic acid, Eluent B: acetonitrile+0.1%formic acid; Gradient: 0.0 min 5% B→5.0 min 10% B→6.0 min 10% B;Temperature: 50° C.; flow rate: 1.0 ml/min; UV detection: 210 nm.

Method 3 (HPLC)

Instrument: HP 1100 with DAD detection; column: Kromasil RP- 18, 60 mm×2mm, 3.5 μm; Eluent: A=5 ml HClO₄/l H₂O, B=ACN; Gradient: 0 min 2% B, 0.5min 2% B, 4.5 min 90% B, 6.5 min 90% B; flow rate: 0.75 ml/min; Temp.:30° C.; detection UV 210 nm.

Preparative RP-HPLC

Column: YMC-Gel; Eluent: acetonitrile/water (Gradient); flow rate: 50ml/min; Temp.: 25° C.; detection UV 210 nm.

Starting Compounds

EXAMPLE 1A 1-(2-Chlorobenzyl)hydrazine

2.74 g (54.75 mmol) of hydrazine hydrate are introduced into 10 ml ofmethanol, and a solution of 3.00 g (14.60 mmol) of 2-chlorobenzylbromide in 5 ml of methanol is added at RT. The temperature rises to35-40° C. during this, and the mixture is then stirred at RT for 3hours. The solvent is removed in vacuo, and the residue is taken up in100 ml of diethyl ether, dried over magnesium sulfate and filtered off.

Total yield: 2.34 g (100% of theory)

LC/MS (Method 2): R_(t)=0.37 min

MS (EI): m/z=157 (M+H)⁺

¹H-NMR (200 MHz, DMSO-d₆): δ=3.29-3.59 (s, 2H), 3.84 (s, 2H), 7.18-7.56(m, 4H), 10.22 (br. s, 1H).

EXAMPLE 2A 1-(2,3-Difluorobenzyl)hydrazine

Preparation takes place in analogy to that described in Example 1 A from2.74 g (54.75 mmol) of hydrazine hydrate and 3.02 g (14.60 mmol) of2,3-difluorobenzyl bromide. For work up, the residue is purified byflash chromatography (mobile phase: dichloromethane:methanol 30:1-10:1).

Total yield: 1.51 g (65% of theory)

LC/MS (Method 2): R_(t)=0.32 min

MS (EI): m/z=159 (M+H)⁺

¹H-NMR (200 MHz, DMSO-d₆): δ=3.75-3.88 (m, 2H), 4.61-4.94 (br. s, 3H),7.07-7.39 (m, 3H).

Preparation of the following compounds takes place in analogy to thatdescribed in Example 1 A: Example Structure Analytical data 3A

HPLC (Method 3): R_(t) = 3.28 min MS (EI): m/z = 191 (M + H)⁺ ¹H-NMR(300 MHz, CDCl₃): δ =5.21 (s, 2H), 7.32-7.45 (m, 2H), 7.49-7.72 (m, 5H).4A

LC/MS (Method 2): R_(t) = = 0.32 min MS (EI): m/z = 159 (M + H)⁺ ¹H-NMR(300 MHz, DMSO- d₆): δ =3.69 (s, 2H), 6.93-7.33 (m, 4H), 7.40-7.56 (m,2H). 5A

LC/MS (Method 2): R_(t) = 0.30 min MS (EI): m/z = 153 (M + H)⁺ ¹H-NMR(200 MHz, DMSO- d₆): δ = 3.65 (s, 3H), 6.85 (s, 2H), 6.84-7.03 (m, 3H),7.15-7.36 (m, 3H), 7.43 (dd, 1H).

EXAMPLE 6 A Sodium (1E)-1-cyano-3-ethoxy-3-oxo-1-propen-2-olate

517 g (7.60 mol) of sodium methoxide are introduced into 3000 ml ofdiethyl ether and, while cooling in ice, 1121 g (7.60 mol) of diethyloxalates are added over the course of 35 minutes. The mixture is stirredfor 15 minutes and again cooled. 312 g (7.60 mol) of acetonitrile areadded dropwise over the course of 20 minutes. The mixture is stirred atRT overnight, and the resulting crystals are filtered off with suction,washed with diethyl ether and dried.

Total yield: 1030 g (83% of theory)

¹H-NMR (300 MHz, CDCl₃): δ=1.27 (t, 3H), 4.17 (q, 2H), 7.60 (s, 1H).

EXAMPLE 7 A Ethyl 5-amino-1-(2-chlorobenzyl)-1H-pyrazole-3-carboxylate

2.29 g (14.60 mmol) of 1-(2-chlorobenzyl)hydrazine from Example 1 A aredissolved in 60 ml of dioxane under argon. To this are added 2.38 g814.60 mmol) of sodium (1E)-1-cyano-3-ethoxy-3-oxo-1-propen-2-olate fromExample 6 A and 2.66 g (1.80 ml; 23.36 mmol) of trifluoroacetic acid.The mixture is boiled under reflux overnight and reacted further withoutfurther workup.

LC/MS (Method 2): R_(t)=2.45 min

MS (El): m/z=280 (M+H)⁺

EXAMPLE 8 A Ethyl5-amino-1-(2,3-difluorobenzyl)-1H-pyrazole-3-carboxylate

Preparation takes place in analogy to that described in Example 7 A from1.50 g (9.48 mmol) of 1-(2,3-difluorobenzyl)hydrazine from Example 2 A,1.55 g (9.48 mmol) of sodium(1E)-1-cyano-3-ethoxy-3-oxo-1-propen-2-olate from Example 6 A, 1.73 g(1.17 ml; 15.18 mmol) of trifluoroacetic acid and 40 ml of dioxane.

LC/MS (Method 1): R_(t)=3.90 min

MS (El): m/z=282 (M+H)⁺

¹H-NMR (200 MHz, DMSO-d₆): δ=1.24 (t, 3H), 4.18 (q, 2H), 4.19-4.46 (br.s, 2H), 5.32 (s, 2H), 5.76 (s, 1H), 6.59-6.72 (m, 1H), 7.07-7.24 (m,1H), 7.27-7.46 (m, 1H).

The preparation of the following compounds takes place in analogy tothat described in Example 7 A: Example Structure Analytical data  9A

LC/MS (Method 2): R_(t) = 2.72 min MS (EI): m/z = 314 (M + H)⁺ ¹H-NMR(200 MHz, DMSO-d₆): δ = 1.14-1.42 (m, 3H), 4.12-4.26 (m, 2H), 5.40 (s,2H), 7.42-7.88 (m, 7H). 10A

LC/MS (Method 2): R_(t) = 2.34 min MS (EI): m/z = 282 (M + H)⁺ ¹H-NMR(200 MHz, DMSO-d₆): δ = 1.16-1.36 (m, 3H), 4.10-4.30 (m, 2H), 5.22 (s,2H), 6.85-7.15 (m, 4H), 7.21-7.37 (m, 2H). 11A

LC/MS (Method 2): R_(t) = 2.31 min MS (EI): m/z = 276 (M + H)⁺ ¹H-NMR(300 MHz, DMSO-d₆): δ = 1.20-1.33 (m, 3H), 3.65 (s, 3H), 4.15-4.29 (m,2H), 5.11-5.16 (m, 2H), 6.78-7.07 (m, 5H), 7.16-7.33 (m, 2H).

EXAMPLE 12 A Ethyl1-(2-chlorobenzyl)-1H-pyrazole[3,4-b]pyridine-3-carboxylate

1.99 g (1.35 ml; 17.52 mmol) of trifluoroacetic acid and 1.45 g (14.60mmol) of 3-dimethylaminoacroleine are added under argon to the solutionof 4.08 g (14.60 mmol) of ethyl5-amino-1-(2-chlorobenzyl)-1H-pyrazole-3-carboxylate from Example 7 A.The mixture is boiled under reflux for 3 hours and worked up by removingthe solvent in vacuo. The residue is purified by flash chromatography onsilica gel (mobile phase: cyclohexane:ethyl acetate 7:1).

Total yield: 2.94 g (64% of theory)

LC/MS (Method 1): R_(t)=4.74 min

MS (EI): m/z=316 (M+H)⁺

¹H-NMR (300 MHz, DMSO-d₆): δ=1.37 (t, 3H), 4.41 (q, 2H), 5.91 (s, 2H),7.00-7.08 (m, 1H), 7.12-7.22 (m, 1H), 7.34-7.43 (m, 1H), 7.46-7.49 (m,1H), 7.83 (d, 1H), 8.50 (dd, 1H), 8.71 (dd, 1H).

EXAMPLE 13 A Ethyl1-(2,3-difluorobenzyl)-1H-pyrazole[3,4-b]pyridine-3-carboxylate

Preparation takes place in analogy to that described in Example 12 Afrom 4.11 g (14.60 mmol) of ethyl5-amino-1-(2,3-difluorobenzyl)-1H-pyrazole-3-carboxylate from Example 8A, 1.99 g (1.35 ml; 17.52 mmol) of trifluoroacetic acid and 1.45 g(14.60 mmol) of 3-dimethylaminoacroleine.

Total yield: 1.94 g (29% of theory)

LC/MS (Method 1): R_(t)=3.31 min

MS (EI): m/z=318 (M+H)⁺

¹H-NMR (300 MHz, DMSO-d₆): δ=1.37 (t, 3H), 4.41 (q, 2H), 5.91 (s, 2H),7.00-7.08 (m, 1H), 7.11-7.22 (m, 1H), 7.33-7.45 (m, 1H), 7.49 (dd, 1H),8.50 (dd, 1H), 8.71 (dd, 1H).

Preparation of the following compounds takes place in analogy to thatdescribed in Example 12 A: Example Structure Analytical data 14A

LC/MS (Method 2): R_(t) = 3.62 min MS (EI): m/z = 350 (M + H)⁺ 15A

LC/MS (Method 2): R_(t) = 3.31 min MS(EI): m/z = 318 (M + H)⁺ ¹H-NMR(200 MHz, CDCl₃): δ = 1.48 (t, 3H), 4.53 (q, 2H), 5.85 (s, 2H),6.67-6.92 (m, 2H), 7.04-7.21 (m, 1H), 7.26-7.37 (m, 1H), 8.53 (dd, 1H),8.63 (dd, 1H). 16A

LC/MS (Method 1): R_(t) = 3.22 min MS (EI): m/z = 312 (M + H)⁺ ¹H-NMR(200 MHz, DMSO-d₆): δ = 1.37 (t, 3H), 3.78 (s, 3H), 4.40 (q, 2H), 5.77(s, 2H), 6.69-6.89 (m, 2H), 6.98-7.09 (m, 1H), 7.29 (dt, 1H), 7.47 (dd,1H), #8.50 (dd, 1H), 8.69 (dd, 1H).

EXAMPLE 17A 1-(2-Chlorobenzyl)-1H-pyrazole[3,4-b]pyridine-3-carboxamide

At room temperature, 2.94 g (9.31 mmol) of ethyl1-(2-chlorobenzyl)-1H-pyrazole[3,4-b]pyridine-3-carboxylate from Example12 A are suspended in 50 ml of 5.5 molar ammonia solution in methanol.The mixture is stirred at RT for 16 hours and evaporated to drynessagain in a rotary evaporator. The residue is again mixed with 50 ml ofammonia solution and stirred at 50° C. for 3 hours. This is repeatedover 3 days. After the last drying, the residue is taken up in 40 ml ofdiethyl ether, and the resulting crystals are filtered off with suctionand dried. The mother liquor is again concentrated in a rotaryevaporator and the mixture is again mixed with 50 ml of ammonia solutionand stirred in an autoclave under autogenous pressure at 80° C. Theresidue is purified by flash chromatography on silica gel (mobile phase:cyclohexane:ethyl acetate 5:1).

Total yield: 1.33 g (50% of theory)

LC/MS (Method 1): R_(t)=4.09 min

¹H-NMR (300 MHz, DMSO-d₆): δ=5.85 (s, 2H), 6.87 (dd, 1H), 7.25 (dt, 1H),7.34 (dt, 1H), 7.40 (dd, 1H), 7.51 (dd, 1H), 7.78 (br. s, 2H), 8.58 (dd,1H), 8.64 (dd, 1H).

EXAMPLE 18A1-(2,3-Difluorobenzyl)-1H-pyrazole[3,4-b]pyridine-3-carboxamide

At room temperature, 1.90 g (5.99 mmol) of ethyl1-(2,3-difluorobenzyl)-1H-pyrazole[3,4-b]pyridine-3-carboxylate fromExample 13 A are suspended in 50 ml of 5.5 molar ammonia solution inmethanol. The mixture is stirred at RT for 16 hours and then evaporatedto dryness in a rotary evaporator. Dichloromethane is added andevaporated to dryness in a rotary evaporator twice more.

Total yield: 0.87 g (50% of theory)

LC/MS (Method 1): R_(t)=4.00 min

¹H-NMR (200 MHz, DMSO-d₆): δ=5.86 (s, 2H), 6.90-7.03 (m, 1H), 7.07-7.22(m, 1H), 7.29-7.49 (m, 2H), 7.71 (d, 2H), 8.57 (dd, 1H), 8.66 (dd, 1H).

Preparation of the following compounds takes place in analogy to thatdescribed in Example 17 A: Example Structure Analytical data 19A

LC/MS (Method 1): R_(t) =4.36 min ¹H-NMR (200 MHz, DMSO-d₆): δ = 5.96(s, 2H), 6.66-6.81 (m, 1H), 7.42 (dd, 1H), 7.49-7.62 (m, 3H), 7.82 (dd,2H), 8.55-8.74 (m, 2H). 20A

LC/MS (Method 1): R_(t) =3.31 min ¹H-NMR (200 MHz, DMSO-d₆): δ = 5.77(s, 2H), 7.04 (dt, 1H), 7.20-7.45 (m, 3H), 7.56 (s, 1H), 7.82 (s, 1H),8.56 (dd, 1H), 8.65 (dd, 1H). 21A

LC/MS (Method 1): R_(t) =3.90 min MS (EI): m/z =283 (M + H)⁺ ¹H-NMR (200MHz, DMSO-d₆): δ = 3.83 (s, 3H), 5.73 (s, 2H), 6.61 (dd, 1H), 6.81 (dt,1H), 7.04 (dd, 1H), 7.26 (dt, 1H), 7.38 (dd, 1H), 7.52 (s, 1H), 7.81 (s,1H), 8.51-8.71 (m, 2H).

EXAMPLE 22 A1-(2-Chlorobenzyl)-1H-pyrazole[3,4-b]pyridine-3-carbonitrile

1.19 g (4.16 mmol) of1-(2-chlorobenzyl)-1H-pyrazole[3,4-b]pyridine-3-carboxamide from Example17 A are suspended in 30 ml of THF, and 0.84 g (0.86 ml; 10.66 mmol) ofpyridine and 3.00 g (1.75 ml; 10.66 mmol) of trifluoroacetic anhydrideare added. The mixture is stirred at room temperature overnight. Themixture is then poured into 300 ml of water and extracted three timeswith ethyl acetate. The combined organic phases are washed withsaturated sodium bicarbonate solution and saturated sodium chloridesolution, dried with magnesium sulfate and concentrated in a rotaryevaporator.

Total yield: 0.880 g (79% of theory)

LC/MS (Method 1): R_(t)=4.70 min

MS (EI): m/z=269 (M+H)⁺

¹H-NMR (200 MHz, DMSO-d₆): δ=5.92 (s, 2H), 7.18 (dd, 1H), 7.26-7.44 (m,2H), 7.47-7.61 (m, 2H), 8.52 (dd, 1H), 8.80 (dd, 1H).

EXAMPLE 23 A1-(2,3-Difluorobenzyl)-1H-pyrazole[3,4-b]pyridine-3-carbonitrile

Preparation takes place in analogy to that described in Example 22 Awith 0.84 g (2.91 mmol) of1-(2,3-difluorobenzyl)-1H-pyrazole[3,4-b]pyridine-3-carboxamide fromExample 18 A, 0.59 g (0.60 ml; 7.46 mmol) of pyridine and 2.10 g (1.22ml; 7.46 mmol) of trifluoroacetic anhydride.

Total yield: 0.784 g (99% of theory)

LC/MS (Method 2): R_(t)=3.22 min

MS (EI): m/z=271 (M+H)⁺

¹H-NMR (200 MHz, DMSO-d₆): δ=5.93 (s, 2H), 7.04-7.28 (m, 2H), 7.33-7.51(m, 1H), 7.52-7.63 (m, 1H), 8.51 (dd, 1H), 8.81 (dd, 1H).

Preparation of the following compounds takes place in analogy to thatdescribed in Example 22 A: Example Structure Analytical data 24A

LC/MS (Method 2): R_(t) =4.05 min MS (EI): m/z =303 (M + H)⁺ ¹H-NMR(MHz, 200): δ =6.00 (s, 2H), 7.08 (d, 1H), 7.50-7.70 (m, 3H), 7.82 (d,1H), 8.53 (dd, 1H), 8.78 (dd, 1H). 25A

LC/MS (Method 1): R_(t) =4.80 min MS (EI): m/z =271 (M + H)⁺ ¹H-NMR (300MHz, DMSO-d₆): δ = 5.86 (s, 2H), 7.10 (dd, 1H), 7.28 (dd, 1H), 7.46(dddd, 1H), 7.55 (dddd, 1H), 8.47 (d, 1H), 8.79 (d, 1H). 26A

LC/MS (Method 2): R_(t) =3.75 min MS (EI): m/z =265 (M + H)⁺ ¹H-NMR (200MHz,): δ = 3.74 (s, 3H), 5.78 (s, 2H), 6.80-7.00 (m, 2H), 7.04 (d, 1H),7.31 (ddd, 1H), 7.52 (dd, 1H), 8.50 (dd, 1H), 8.79 (dd, 1H).

EXAMPLE 27 A1-(2-Chlorobenzyl)-1H-pyrazole[3,4-b]pyridine-3-carboximidamidehydrochloride

380 mg (1.41 mmol) from Example 22 A are suspended in 6 ml of methanolunder argon. 45.84 mg (0.85 mmol) of sodium methoxide are added thereto,and the mixture is stirred at 50° C. for 5 hours. Then 189.12 mg (3.54mmol) of ammonium chloride are added thereto, and the mixture is stirredunder reflux for 2 hours. The reaction solution is concentrated in vacuoin a rotary evaporator, and the residue is suspended in 25 ml ofsaturated sodium carbonate solution and extracted three times with 75 mlof ethyl acetate each time. The combined organic phases are dried overmagnesium sulfate, filtered and dried. The residue is taken up in 50 mlof diethyl ether and the product is precipitated with 4 normalhydrochloric acid in dioxane. The precipitate is filtered and driedunder high vacuum.

Total yield: 0.200 g (44% of theory)

LC/MS (Method 2): R_(t)=1.51 min

MS (EI): m/z=286 (M+H−HCl⁺)

¹H-NMR (300 MHz, DMSO-d₆): δ=5.95 (s, 2H), 7.07 (dd, 1H), 7.29 (dt, 1H),7.37 (dt, 1H), 7.49-7.59 (m, 2H), 8.58 (dd, 1H), 8.77 (dd, 1H), 9.42(br. s, 4H).

EXAMPLE 28 A1-(2,3-Difluorobenzyl)-1H-pyrazole[3,4-b]pyridine-3-carboximidamidehydrochloride

760 mg (2.81 mmol) from Example 23 A are suspended in 10 ml of methanolunder argon. 30.4 mg (0.56 mmol) of sodium methoxide are added thereto,and the mixture is stirred at RT for 4 hours. Then 225.6 mg (4.22 mmol)of ammonium chloride are added thereto, and the mixture is stirred at RTfor 5 hours. After addition of 20.5 mg of concentrated hydrochloricacid, the temperature is again reduced to RT and the product is freed ofsolvent in vacuo. The residue is suspended in 10% strength sodiumcarbonate solution and extracted three times with ethyl acetate. Thecombined organic phases are dried, filtered and dried. The residue istaken up in 15 ml of diethyl ether, and the product is precipitated with1 molar hydrochloric acid in dioxane. The precipitate is filtered anddried under high vacuum.

Total yield: 0.775 g (76% of theory)

LC/MS (Method 1): R_(t)=2.65 min

MS (EI): m/z=288 (M+H)⁺

¹H-NMR (300 MHz, DMSO-d₆): δ=5.94 (s, 2H), 7.08-7.24 (m, 1H), 7.34-7.47(m, 1H), 7.54 (dd, 1H), 8.55 (dd, 1H), 8.78 (dd, 1H), 9.39 (br. s, 4H).

Preparation of the following compounds takes place in analogy to thatdescribed in Example 27 A: Example Structure Analytical data 29A

LC/MS (Method 2): R_(t) = 2.45 min MS (EI): m/z = 320 (M +H)⁺ ¹H-NMR(MHz, 200, DMSO-d₆): δ = 6.02 (s, 2H), 6.95 (m_(c),1H), 7.48-7.66 (m,3H), 7.81 (m_(c), 1H), 8.60 (dd, 1H), 8.77 (dd, 1H), 9.2-9.6 (m, 3H).30A

LC/MS (Method 2): R_(t) =2.32 min MS (EI): m/z = 288 (M +H)⁺ ¹H-NMR (400MHz, DMSO-d₆): δ = 5.84 (s, 2H), 7.04 (dd, 1H), 7.27 (dd, 1H), 7.39(ddd, 1H), 7.49 (dd, 1H), 8.56 (d, 1H), 8.73 (d, 1H), 9.3 (br. S, 3H).31A

LC/MS (Method 2): R_(t) =2.18 min MS (EI): m/z = 282 (M +H)⁺ ¹H-NMR(MHz, 200, DMSO-d₆ ): δ = 3.81 (s, 3H), 5.82 (s, 2H), 6.77-6.91 (m, 2H),7.04 (d, 1H), 7.29 (m_(c), 1H), 7.53 (dd, 1H), 8.56 (dd, 1H), 8.78 (dd,1H), 9.3-9.6 (m, 3H).

EXAMPLE 32 A 4-[(Dimethylamino)methylene]pyridineacetonitrile (E/Zmixture)

4-Pyridylacetonitrile 7.52 g (63.7 mmol) andtert-butoxybis(dimethylamino)methane 11.09 g (63.7 mmol) are stirred at100° C. for 2 h. During this, liberated dimethylamine and t-butanol isdischarged to the atmosphere by means of a vacuum pump through a gentlereduced pressure flow. Flash chromatography (dichloromethane/ethylacetate 50:1->20:1) affords the title compound.

Yield: 10.2 g (93% of theory)

R_(f)-Wert: 0.29 (dichloromethane/EA 20/1)

¹H-NMR (300 MHz, DMSO-d₆): δ=3.25 (s, 6 H, 2×CH₃), 7.25 (d, 2 H, Ar—H),7.80 (s, 1 H, Ar—H), 8.33 (d, 2 H, Ar—H).

MS (ESI pos.): m/z=174 ([M+H]⁺)

EXAMPLE 33 A1-(2-Fluorobenzyl)1H-pyrazolo[3,4-b]pyridine-3-carboxamidine

33 A-1 Ethyl 5-amino-1-(2-fluorobenzyl)pyrazole-3-carboxylate

111.75 g (75 ml, 0.98 mol) of trifluoroacetic acid are added to 100 g(0.613 mol) of sodium salt of ethyl cyanopyruvate (prepared in analogyto Borsche and Manteuffel, Liebigs Ann. 1934, 512, 97) in 2.5 l ofdioxane under argon with efficient stirring at room temperature, and themixture is stirred for 10 minutes during which much of the precursordissolves. Then 85.93 g (0.613 mol) of 2-fluorobenzylhydrazine areadded, and the mixture is boiled overnight. After cooling, the crystalsof sodium trifluoroacetate which have separated out are filtered offwith suction and washed with dioxane, and the solution is reactedfurther as it is.

33 A-2 Ethyl 1-(2-fluorobenzyl)-1H-pyrazolo[3,4-b]pyridine-3-carboxylate

The solution obtained from Example 33 A-1 is mixed with 61.25 ml (60.77g, 0.613 mol) of dimethylaminoacrolein and 56.28 ml (83.88 g, 0.736 mol)of trifluoroacetic acid and boiled under argon for 3 days. The solventis then evaporated in vacuo, and the residue is added to 2 l of waterand extracted three times with 1 l of ethyl acetate each time. Thecombined organic phases are dried with magnesium sulfate andconcentrated in a rotary evaporator. Chromatography is carried out on2.5 kg of silica gel, eluting with a toluene/toluene-ethyl acetate=4:1gradient. Yield: 91.6 g (50% of theory over two stages).

m.p. 85° C.

R_(f) (SiO₂, toluene/ethyl acetate 1:1): 0.83

33 A-3 1-(2-Fluorobenzyl)-1H-pyrazolo[3,4-b]pyridine-3-carboxamide

10.18 g (34 mmol) of the ester obtained in Example 33 A-2 are introducedinto 150 ml of methanol which has been saturated with ammonia at 0-10°C. The mixture is stirred at room temperature for two days and thenconcentrated in vacuo. R_(f) (SiO₂, toluene/ethyl acetate 1:1): 0.33

33 A-4 3-Cyano-1-(2-fluorobenzyl)-1H-pyrazolo[3,4-b]pyridine

36.1 g (133 mmol) of1-(2-fluorobenzyl)-1H-pyrazolo[3,4-b]pyridine-3-carboxamide from Example33 A-3 are dissolved in 330 ml of THF, and 27 g (341 mmol) of pyridineare added. Then, over the course of 10 minutes, 47.76 ml (71.66 g, 341mmol) of trifluoroacetic anhydride are added, during which thetemperature rises to 40° C. The mixture is stirred at room temperatureovernight. It is then added to 1 l of water and extracted three timeswith 0.5 l of ethyl acetate each time. The organic phase is washed withsaturated sodium bicarbonate solution and with 1 N hydrochloric acid,dried with magnesium sulfate and concentrated in a rotary evaporator.

Yield: 33.7 g (100% of theory)

m.p.: 81° C.

R_(f) (SiO₂, toluene/ethyl acetate 1:1): 0.74

33 A-5 Methyl(2-fluorobenzyl)-1H-pyrazolo[3,4-b]pyridine-3-carboximidate

30.37 g (562 mmol) of sodium methoxide are dissolved in 1.5 l ofmethanol, and 36.45 g (144.5 mmol) of3-cyano-1-(2-fluorobenzyl)-1H-pyrazolo[3,4-b]pyridine (from Example 33A-4) are added. The mixture is stirred at room temperature for 2 hoursand the resulting solution is employed directly for the next stage.

33 A-6 1-(2-Fluorobenzyl)-1H-pyrazolo[3,4-b]pyridine-3-carboximidamide

The solution of methyl(2-fluorobenzyl)-1H-pyrazolo[3,4-b]pyridine-3-carboximidate in methanolobtained from Example 33 A-5 is mixed with 33.76 g (32.19 ml, 562 mmol)of glacial acetic acid and 9.28 g (173 mmol) of ammonium chloride andstirred under reflux overnight. The solvent is evaporated in vacuo, theresidue is thoroughly triturated with acetone, and the precipitatedsolid is filtered off with suction.

¹H-NMR (DMSO-d₆, 200 MHz): δ=5.93 (s, 2H); 7.1-7.5 (m, 4 H); 7.55 (dd,1H); 8.12 (dd, 1H); 8.30 (dd, 1H); 9.5 (bs, 4H exchangeable) ppm.

MS (El): m/z=270.2 (M−HCl)

EXAMPLE 34 A2-[1-[(2-fluorophenyl)methyl]-1H-pyrazolo[3,4-b]pyridin-3-yl]-5-(4-pyridinyl)-4-pyrimidinamine

0.50 g (1.9 mmol) of1-(2-fluorobenzyl)-1H-pyrazolo[3,4-b]pyridine-3-carboximidamide fromExample 33 A and 4-[(dimethylamino)methylene]pyridineacetonitrile (0.32g, 1.9 mmol) from Example 32 A are suspended in xylene, and BF₃*OEt₂ (71μl, 79 mg, 0.56 mmol, 0.3 equiv.) is added. After 19 h at 140° C., themixture is allowed to cool to room temperature and concentrated invacuo. The title compound is purified by flash chromatography on silicagel (dichloromethane:methanol 20:1) and subsequent stirring inacetonitrile.

Yield: 0.24 g (33% of theory)

R_(f): 0.17 (EA/methanol 20:1)

m.p.: 254° C.

Retention time: R_(t)=2.7 min (column: Symmetry, C-18, 3.5 μm, 50×2.1mm, flow rate 0.5 ml/min, 40° C., Gradient: water (+0.1% formic acid):acetonitrile (+0.1% formic acid) at 0 min: 90:10, at 7.5 min 10:90))

¹H-NMR (300 MHz, DMSO-d₆): δ=5.81 (s, 2H, CH₂), 7.0-7.6 (m, 9 H, Ar—H,NH₂), 8.64 (m_(c), 3 H, Ar—H), 9.05 (d, 1 H, Ar—H)

MS (ESI pos.): m/z=398 ([M+H]⁺)

MS (ESI neg.): m/z=396 ([M−H]⁺)

EXAMPLE 35 A2-(1H-Pyrazolo[3,4-b]pyridin-3-yl)-5-(4-pyridinyl)-4-pyrimidinamine

Approx. 15 ml of ammonia are condensed in a flask cooled with dry ice.0.347 g (0.015 mol) of sodium is added thereto, and the mixture isstirred for 30 minutes. Then 1.50 g (0.004 mol) of the compound fromExample 34 A are added thereto, and the mixture is stirred for 3 hours.1.21 g (0.023 mol) of ammonium chloride are added to the mixture, andthe remaining ammonia is evaporated off overnight through a scrubbingtower. For work up, water is added, and the crystals are filtered offwith suction and dried. The residue is purified by column chromatography(mobile phase: dichloromethane:methanol 8:2) and then by RP-HPLC.

Total yield: 0.50 g (65% of theory)

LC/MS (Method 2): R_(t)=1.09 min

MS (EI): m/z=290 (M+H)⁺

¹H-NMR (200 MHz, DMSO-d₆): δ=6.57 (br. s, 2H), 7.25 (dd, 1H), 7.52 (dd,2H), 7.90 (s, 1H), 8.29 (s, 1H), 8.55 (dd, 1H), 8.70 (dd, 2H), 9.03 (dd,1H).

Exemplary Embodiments

EXAMPLE 12-[1-(2-Chlorobenzyl)-1H-pyrazolo[3,4-b]pyridin-3-yl]-5-(4-pyridinyl)-4-pyrimidinamine

410 mg (1.27 mmol) of1-(2-chlorobenzyl)-1H-pyrazole[3,4-b]pyridine-3-carboximidamidehydrochloride from Example 27 A and 242.46 mg (1.40 mmol) of4-[(dimethylamino)methylene]pyridineacetonitrile from Example 32 A aresuspended in a 3:1 benzyl alcohol:isobutanol mixture at RT. Then 25.75mg (0.25 mmol) of triethylamine are added, and the mixture is stirred at113° C. overnight. The solvent is then removed in vacuo, and the productis absorbed on silica gel. It is chromatographed (mobile phase:dichloromethane:methanol 30:1). The combined pure fractions arerecombined and purified by preparative RP-HPLC.

Total yield: 70 mg (13% of theory)

LC/MS (Method 1): R_(t)=3.52 min

MS (EI): m/z=414 (M+H)⁺

¹H-NMR (400 MHz, DMSO-d₆): δ=5.89 (s, 2H), 6.95 (d, 1H), 7.14 (br. s,2H), 7.27 (t, 1H), 7.35 (t, 1H), 7.41 (dd, 1H), 7.50-7.58 (m, 3H), 8.28(s, 1H), 8.61-8.73 (m, 3H), 9.07 (dd, 1H).

EXAMPLE 22-[1-(2,3-Difluorobenzyl)-1H-pyrazolo[3,4-b]pyridin-3-yl]-5-(4-pyridinyl)-4-pyrimidinamine

680 mg (1.88 mmol) of1-(2,3-difluorobenzyl)-1H-pyrazolo[3,4-b]pyridine-3-carboximidamidehydrochloride from Example 28 A and 358 mg (2.07 mmol) of4-[(dimethylamino)methylene]pyridineacetonitrile from Example 32 A aresuspended in a 3:1 benzyl alcohol:isobutanol mixture at RT. Then 38.1 mg(0.38 mmol) of triethylamine are added, and the mixture is stirred at87-90° C. overnight. A further 0.5 eq. of4-[(dimethylamino)methylene]pyridineacetonitrile from Example 32 A isadded, and the mixture is stirred at 87-90° C. for a further 6 hours. Itis diluted with 3 ml of benzyl alcohol and 19 ml of isobutanol andbriefly heated at 113° C. It is filtered hot, and the filtrate is slowlycooled while stirring. The solvent is then removed in vacuo, and theproduct is absorbed on silica gel. It is chromatographed (mobile phase:dichloromethane:methanol 30:1-20:1). The combined pure fractions arerecombined and purified by preparative RP-HPLC.

Total yield: 180 mg (23% of theory)

LC/MS (Method 1): R_(t)=3.24 min

MS (EI): m/z=416 (M+H)⁺

¹H-NMR (200 MHz, DMSO-d₆): δ=5.89 (s, 2H), 6.95-7.08 (m, 1H), 7.09-7.26(m, 3H), 7.30-7.48 (m, 2H), 7.54 (dd, 2H), 8.28 (s, 1H), 8.61-8.73 (m,3H), 9.05 (dd, 1H).

The following compounds are prepared in analogy to Example 1: ExampleStructure Analytical data 3

LC/MS (Method 2): R_(t) = 3.02 min MS (EI): m/z = 448 (M + H)⁺ ¹H-NMR(300 MHz, DMSO-d₆): δ = 5.99 (s, 2H), 6.80 (d, 1H), 7.1 (br. s, 2H),7.41 (dd, 1H), 7.47-7.6 (m, 4H), 7.83 (dd, 1H), 8.30 (s, 1H), 8.6-8.7(m, 3H), 9.08 (d, 1H). 4

LC/MS (Method 2): R_(t) = 2.80 min d₆): MS (EI): m/z = 416 (M + H)⁺¹H-NMR (300 MHz, DMSO-d₆): δ = 5.32 (s, 2H), 7.0-7.2 (m, 3H), 7.2-7.45(m, 3H), 7.54 (dd, 2H), 8.28 (s, 1H), 8.61-8.73 (m, 3H), 9.04 (dd, 1H).5

LC/MS (Method 2): R_(t) = 2.73 min MS (EI): m/z = 410 (M + H)⁺ ¹H-NMR(300 MHz, DMSO-d₆): δ = 5.75 (s, 2H), 6.22 (d, 1H), 6.82 (dd, 1H),7.0-7.2 (m, 3H), 7.27 (dd, 1H), 7.38 (dd, 1H), 7.53 (d, 2H), 8.28 (s,1H), 8.61 #(dd, 1H), 8.69 (d, 2H), 9.04 (d, 1H).

EXAMPLE 62-({3-[4-Amino-5-(4-pyridinyl)-2-pyrimidinyl]-1H-pyrazolo[3,4-b]pyridin-1-yl}-methyl)benzonitrile

60 mg (0.21 mmol) of2-(1H-pyrazolo[3,4-b]pyridin-3-yl)-5-(4-pyridinyl)-4-pyrimidinylaminefrom Example 35 A are suspended in 6 ml of dimethylformamide underargon. Addition of 26.38 mg (0.25 mmol) of sodium carbonate is followedby stirring at 50° C. for one hour. Then 40.66 mg (0.21 mmol) of2-cyanobenzyl bromide are added thereto, and the mixture is stirred at50° C. overnight. For work up, the mixture is filtered and the filtrateis adjusted to pH 4-5 with 1 normal hydrochloric acid and purified bypreparative RP-HPLC.

Total yield: 40 mg (48% of theory)

LC/MS (Method 2): R_(t)=1.84 min

MS (EI): m/z=405 (M+H)⁺

¹H-NMR (300 MHz, DMSO-d₆): δ=5.99 (s, 2H), 6.69 (s, 1H), 7.02-7.17 (m,2H), 7.22 (d, 1H), 7.41 (dd, 1H), 7.47-7.57 (m, 2H), 7.59-7.68 (m, 1H),7.85-7.94 (m, 1H), 8.28 (s, 1H), 8.63-8.69 (m, 3H), 9.06 (dd, 1H).

1. A compound of the formula (I)

in which R¹ is chlorine, cyano, trifluoromethyl or methoxy, and R² ishydrogen or fluorine, or R¹ is fluorine, and R² is fluorine, or apharmaceutically acceptable salt.
 2. The compound of the formula (Ia) asclaimed in claim 1

in which R^(1a) is selected from the group of

or a pharmaceutically acceptable salt.
 3. The compound of the formula(Ia) as claimed in claim 2, in which R^(1a) is

or a pharmaceutically acceptable salt.
 4. (canceled)
 5. A pharmaceuticalcomposition comprising at least one compound of the formula (I) asdefined in claim 1, and at least one further excipient.
 6. Apharmaceutical composition comprising at least one compound of theformula (I) as defined in claim 1 in combination with at least oneorganic nitrate or NO donor.
 7. A pharmaceutical composition comprisingat least one compound of the formula (I) as defined in claim 1 incombination with at least one compound which inhibits the breakdown ofcyclic guanosine monophosphate (cGMP).
 8. A method for the treatment ofcardiovascular disorders, comprising administering to a patient in needthereof a therapeutically effective amount of a compound of claim
 1. 9.A method for the treatment of hypertension, comprising administering toa patient in need thereof a therapeutically effective amount of acompound of claim
 1. 10. A method for the treatment of thromboembolicdisorders or ischaemias, comprising administering to a patient in needthereof a therapeutically effective amount of a compound of claim
 1. 11.A method for the treatment of sexual dysfunction, comprisingadministering to a patient in need thereof a therapeutically effectiveamount of a compound of claim
 1. 12. The method of any of claims 9 to12, where compounds of the formula (I) as defined in claim 1 areemployed in combination with at least one organic nitrate or NO donor orin combination with at least one compound which inhibits the breakdownof cyclic guanosine monophosphate (cGMP).
 13. The method of claim 11,wherein the sexual dysfunction is erectile dysfunction or female sexualdysfunction.